Demountable wall systems are frequently employed for partitioning room space between an overhead and a floor. The walls can be constructed of wall panels, fabric, sheet rock, etc. which are incorporated into the frame work assembly using either a batten or rolled form snap configuration. The finished or exposed area of a wall surface includes no fasteners. Demountable wall systems can be comprised of prefabricated components including, but not limited to, a supporting framework with support or frame members generally extending vertically from floor to ceiling, wall panels, a means for attaching the panels to the framework, and various trim elements. The wall panels may be held in the framework by battens or by snap-in arrangements wherein the panels have edge flanges engaging recesses in the frame members.
Demountable wall systems may be provided as single-sided, having wall panels on only one side of the framework, or as double sided, having wall panels on both sides of the framework. In double-sided configuration, either the framing elements must have wall panel attachments on both sides, or two sets of one-sided framing elements must be used back to back.
Demountable wall systems may be used as enclosures in which a highly sanitary or an uncontaminated environment may be maintained, also know as “Cleanrooms”. A “Cleanroom” is a specially designed & constructed room in which the air supply, air distribution, filtration of air supply, materials of construction, and operating procedures are regulated to control airborne particle concentrations to meet appropriate cleanliness levels. Cleanrooms have controlled environments in which variables such as the density of airborne particles per cubic meter or the temperature of the room are controlled. For example, Cleanrooms are often used in facilities for the manufacture and assembly of electronic components, or in the biological and pharmaceutical sciences. Cleanrooms are essential for these manufacturing processes, which require high degrees of cleanliness and/or precise temperature and humidity control.
The need for Cleanrooms that can control the level of contamination (e.g. particulate and/or biological, etc.) in the sub micron particle range is increasing. Typical systems have been created to meet a single use, as the requirements for use in electronics, photonics, aerospace, trace metals, pharmaceutical, and for biological safety containment. These varieties in applications require wall systems with different configurations and functional requirements.
The walls and corners of Cleanrooms should have generally flat and smooth surfaces which tend not to catch and accumulate dust and other contaminants and which will not interfere with a laminar flow of room air. The wall surfaces must be smooth and durable to facilitate cleaning. The vertical seams between panel edges should be sealable, even when one or both panel edges have been field cut. The details of the panel edge connections should not interfere with the installation of the panel in tight spaces.
Cleanrooms are classified according to the number and size of particles permitted per volume of air provided in the enclosure. A discrete-particle-counting, light-scattering instrument may be used to determine the concentration of airborne particles, equal to and larger than the specified sizes, at designated sampling locations. The ISO 14644 Standards were based on from previous US Federal Standard 209E Airborne Particulate Cleanliness Classes in Cleanrooms and Cleanzones (abbreviated as the FED-STD-209E standard), which referred to the number of particles of size 0.5 μm or larger permitted per cubic foot of air. The ISO 14644-1 Standards specify the decimal logarithm of the number of particles 0.1 μm or larger permitted per cubic meter of air. For example, an ISO class 5 Cleanroom has at most 105 particles per m3.
Several performance considerations are important in the design, manufacture, and installation of demountable wall systems, including such systems for use in the design, manufacture, and installation of Cleanrooms. For example, it can be desirable that the components of the wall systems have the ability to be delivered to site and with a minimum of field fabrication and installed “clean”. When installed, the wall should present a smooth surface for ease of cleaning. The system should be installable in as little space as possible, as floor space costs are significant. Variations or movement in the floor or ceiling should be accommodated. As such, Cleanrooms typically require modification to meet site conditions during construction, have the ability to be relocated, and should be flexible to allow the system to be easily reconfigured to meet changes required for production and equipment changes. These changes are typically required to be made “clean” so they can be installed during or with little disruption to production.
Previously existing wall systems have failed to satisfy one or more of the above-mentioned criteria. Thus there is an unmet need for a demountable wall system that requires a minimum of field fabrication and can be built “clean”, is economically manufactured, is easily installed in a minimum of space, and is suitable for use in a variety of Cleanroom configurations or as an office or lab partition and otherwise meets all the aforementioned criteria.